OK -
Numerous issues at play.... BUT
This Hack Does Work fine in Ver 6.1 br1I've just installed and got it running.
A couple of notes to be careful of.
General Install tips if you will.
If when you are previewing a post, you are unable to add graemlins... make sure that in mess_reply.tmpl you add the name="replier" part to the SECOND <form tag. The first form just shows you the message to be previewed... the second one is where the editing is done.
Also....
If things aren't working correctly... try a fresh install. Pay special attention to the fact that you are only inserting/changing the parts in RED above. Don't copy and paste the whole line as the rest of the lines may vary from file to file.
So only add/alter the parts Gardener's got in red above.
Hope this clarifies a bit.